It has long been a matter of state of the art to complete a book (magazine) with signatures in a demographic order, that is, signatures in the form of advertisements, return mailing cards and so on oriented to reader interest. The demographics may be geographical, professional, consumer interest and so on.
The signatures are supplied from hoppers or so-called pockets. The cover indeed is the last signature. It is also state of the art to add the name and address of the subscriber to the front of the cover with an ink jet printer. To facilitate mailing, the magazines are usually sequenced in terms of zip code and feeding the signatures demographically has also been programed under the state of the art.